Some pushrod engines, including v-twin motorcycle engines, for example, include external pushrods extending between a hydraulic lifter tappet block and a cylinder head. The pushrods are enclosed in tubes so that the pushrods may move under normal engine operation without external exposure. Pushrod tubes may also provide a secondary oil return passage from the cylinder head and upper portions of a valve train (e.g., rocker arms, valves, valve springs, etc.) to a crankcase.